Light is made of particles called photons, bundles of the electromagnetic field that carry a specific amount of energy. With sufficiently sensitive experiments, you can count photons or even perform measurements on a single one.

– Light is made up of electric and magnetic energy. – Light can travel through a vacuum. What do scientists mean when they describe light as having a wave-particle duality? That light is both a wave and a particle simultaneously. (Light is both at the same time, but we normally can measure one aspect of it at a time.)

A wave transports its energy without transporting matter. Waves are seen to move through an ocean or lake; yet the water always returns to its rest position. Energy is transported through the medium, yet the water molecules are not transported.

L = n / 2 • λ For standing wave patterns, there is a clear mathematical relationship between the length of a string and the wavelength of the wave that creates the pattern.

Standing wave, also called stationary wave, combination of two waves moving in opposite directions, each having the same amplitude and frequency. The phenomenon is the result of interference; that is, when waves are superimposed, their energies are either added together or canceled out.

They stress the electrical network and potentially damage equipment. They may disrupt normal operation of devices and increase operating costs. Symptoms of problematic harmonic levels include overheating of transformers, motors and cables, thermal tripping of protective devices and logic faults of digital devices.

A lower power factor causes a higher current flow for a given load. As the line current increases, the voltage drop in the conductor increases, resulting in a lower voltage at the equipment. With an improved power factor, the voltage drop in the conductor is reduced, improving the voltage at the equipment.

Harmonics Can Cause Overheating and Damage Your Transformers & Motors. When harmonics are present it can cause overheating in transformers. This is an effect of increased I2R losses due to excessive current and skin effect in the transformer core.

Transformers:Harmonics in transformers cause an increase in the iron and copper losses. Voltage distortion increase losses due to hysteresis and eddy currents and causes overstressing of the insulation material used. The primary effect of power line harmonics in transformer is, thus the additional heat generated.

HVDC lines increase the efficiency of transmission lines due to which power is rapidly transferred. In a combined AC and DC system, generated AC voltage is converted into DC at the sending end. Then, the DC voltage is inverted to AC at the receiving end, for distribution purposes.

Voltage harmonics are mostly caused by current harmonics. The voltage provided by the voltage source will be distorted by current harmonics due to source impedance. If the source impedance of the voltage source is small, current harmonics will cause only small voltage harmonics.

Voltage harmonics do not originate directly from non-linear loads. The current harmonics (distorted waveform) flow through system impedance (source and line impedances) and cause harmonic voltage drop across the impedances.

Total harmonic distortion (THD) is a measurement that tells you how much of the distortion of a voltage or current is due to harmonics in the signal. Total harmonic distortion (THD) is a measurement that tells you how much of the distortion of a voltage or current is due to harmonics in the signal.

NOTE: High-voltage systems can have up to 2.0% THD where the cause is an HVDC terminal that will attenuate by the time it is tapped for a user. Even harmonics are limited to 25% of the odd harmonic limits above. Current distortions that result in a dc offset, e.g. half-wave converters, are not allowed.

There are a number of methods to modify adverse system responses to harmonics:

1. Add a shunt filter.
2. Add a reactor to detune the system.
3. Change the capacitor size.
4. Move a capacitor to a point on the system with a different short-circuit impedance or higher losses.